I now have 9000 miles on my car, and on my 6 hour road trip yesterday, I did another calibration of the MPG vs. MPH.

Cruise control at various speed, drive for about 5 miles to let the MID settle

6MT, at 6th gear

55MPH = 38MPG
65MPH = 34MPG
75MPH = 31MPG
85MPH = 27MPG
95MPH = 24MPG
105MPH = 21MPG

It was a bit difficult to keep the speed at 105 for 5 miles, kept coming up to other slow cars.

So for the rest of the way, I set the cruise control at 80MPH, and after 300 miles, it indicated 29MPG.

Going 55MPH would have been great for my wallet, but I would absolutely go crazy driving 4 hours at 55MPH. Come to think of it, if someone has the patience to drive 55MPH for the entire trip, you can get over 600 miles to a tank!

 

nice work!

So that's why I only get 21 mpg.

go figure.
:facelick:

 

So, it is true that one gets higher gas mileage at lower speed (around 55mph)!

Great work!

 

Ha... my 5AT got 32-34 MPG at 50-55 MPH vibration zone.
:o

Thanks for your hard works. That's why we need instant MPG display, just like 05RL.

 

It's the first thing I noticed missing on the TL that my wife's MDX has. Wonder why? In the MDX the info is on the Navi's trip computer window but the TL doesn't have it there or in the MID.

 

What about getting pulled over for speeding, *L*

 

Anyone else notice that there seems to be some strange, direct relationship between the depth of that skinny pedal on the right and the rate of descent of the fuel gauge? Wierd... :lol1:

 

jtruman,

Thanks for posting this. I see those figures roughly, but never took the time to actually test the MPG ratings. Since the gas prices are climbing ever higher, I'm more inclined to get the best milage I can.

 

As I found out to my disappointment tonight, you can get a pseudo-instant-mpg reading by watching the miles-to-entry in the MID. As I left the parking lot at work tonight it indicated 73 miles to empty. As I accelerated up the interstate entrance ramp barely 1.5 miles away, the MID indicated 68 miles. It's not exact enough for an instant mpg, but it's good enough (or bad in this case) for me.

 

I thought the funniest part of this entire experience was what all the other drivers must had been thinking... I was on highway 5 from bay area to LA, where most people average around 80-85MPH.

When I was going 55MPH, even the trucks were passing me. It felt miserably slow on such a straight, flat highway.

Then, not long after that, those same cars and trucks saw me fly right by them going 105MPH...

 

Well, I hope that mine will get better... just went to Austin and only got 28 MPG mostly doing 65 to 70. I would love to get it a bit higher.

 

Great work! I think I remember reading somewhere that the feds chose 55mph as the standard highway speed back in the 70s simply because it gave the best mileage in just about every car. 30 plus years later and it's still the same. Too bad the double nickel is so painfully slow. Again, thanks for the info. Now has anyone done anything similar with the 5AT? I would do it but I'm still at the break in stage.

dsc888

 

Better MPG's is why the Federal Speed limit is 55 mph, But look at the real word impact on MPG

Driving for 4 hours at 55mph brings you a distance of 220 miles, fuel cost =$13.00
Driving for 4 hours at 75mph brings you a didtance of 300 miles, fuel cost =$21.77
* based on $2.25 gal premium, 38mpg(55mph) vs 31mpg (75mph)

Sure you saved $8.77 by driving those 4 hours at 55mph but you drive 80 miles less. To reach the same destination at 55mph as you could at 75mph you need to drive another 1.5 hours. Driving those 1.5 hours extra will cost you another $4.75.

So what did you save really on a 300 mile trip on gas.

At 75mph it cost you $4.02 more in gas but you saved 1.5 hours of your time.
That represents an hourly wage of $2.68 per hour, substantially less than even minimum wage.

 

I have to clarify that these figures were based on very flat, straight road on cruise control. If there's a slight hill, the efficiency goes down significantly (vise versa if you are going down the hill). If you are not in cruise control mode and rely on your feel to stay within 65-70, it may be slightly worse, I think.

Also, if your TL is 5AT, then you should expect about 2-3MPG less than manual.

 

Absolutely, time is money!

 

I have a question, was the A/C on when the test was performed?

 

Good question, I am not sure... probably was on, but at very low setting. It was at night, but the outside temperature was around 75 degrees. My interior temp setting is usually around 72.

I have a general question, I know when the AC is on, the fuel efficiency decreases. Is there a correlation between the temperature differential and fuel efficiency? In other words, on a very very hot day, with the AC working extra hard, would that lead to lower fuel efficiency compared to a normal warm day?

 

Engines perform better when the air intake is cool. So yes your car will perform better on cool day, vs hot days.

Do you have the stock tire size on the car for this MPG test ?

 

Yes, everything stock down to the sh*tty EL42, the original.

 

Acura needs to put the INSTANT economy in the MID. Even my 97 Cherokee had that.

Regardless, cool study.

 

My Dodge Dakota has that - atleast they put a rudimentry trip computer in the 04. I aways thought that was a real slipup on my 02TL-S.

 

I'm wondering if fuel efficiency is very much dependent on RPM and if RPM alone determines MPG.

Great study! 105 is waaay too much though.

 

Those numbers are very impressive for a 270hp car.....

I was expecting 55MPH = 31MPG....the results are better than expected.

 

Through this entire thread, no one brought up the question of wether the MID is correct?

What I mean is this, on my BMW the miles per gallon shown using the trip computer, were never the same as the actual miles driven using the "miles divided by the gallons" method.

The computer always showed I was getting more miles per gallon than I actually was.

 

There have been plenty of threads here that discussed this already. Everyone has said that the MID MPG has been accurate. I can't remember anyone saying it wasn't.

 

It's accurate, at least on my car. I know that because everytime I fill up gas, I look at the MPG relative to total number of miles driven.

I fill up the tank to full everytime. Let's say 300 miles later I decide to get gas and the MPG reads 30MPG. I am almost willing to bet that I would fill exactly 10 gallons to full.

 

Right, the reading is quite accurate if you compare with your own method of "miles divided by gallons". I've done this from Mile 1 to Miles 10k.

That's why no one said this question. :o

 

Thank you marquis, jtruman and rets. :smackhead

 

Very cool study. I just wish my driving could be this steady. Occassionally there are stretches of open road, but not for any extended period of times on the daily commute. If they would just get rid of all those red lights and other cars on the road, I'd get WAY better gas mileage

 

Does this mean that if you go 40 MPH you can get 40 MPG ?

or does it start to diminish below 55 ?

 

5AT.

Not sure where is the best effieicent RPM range for 5th gear. Isn't we able to upshift to 5th while the speed is over 38+ mph? If so and ppl can stand with that strong resonnace of exhaust, I have no doubt that MPG could be good, but may not be closer to 40, IMHO.

 

Good question, next time I drive down to LA, I'll try 45MPH on 6MT.

 

I did my one and only speed test going to L.A. Got my car jsut barely over 150 MPH.. It took forever to get from 140 to 150 though... My MPG read 21mpg after that! Some Mercedes was trying to keep up with me.. he was probably hitting 130-140... I ended up seeing him get smaller and smaller gradually in my rear view mirror.. this TL rocks!

I've NEVER seen my MPG get over 28 in my 6MT.. even when I put it on cruise control at 70mph or 75mph or even 80 for 1-2 hours straight at least. I wonder if I damaged something??

 

I assume you were on highway 5... why not do what I did, cruise control at fixed speed and reset your MID to see how it compares to my 6MT?

The last time I went to LA and did not use cruise control, I averaged around 25-27 driving 75MPH - 80MPH.

This time I set the cruise control at 74MPH, and I was quite proud the entire trip averaged 30MPH. It makes a big difference whether you are cruise controller or not. I guess the computer is far more efficient (and patient) at controling the throttle than I could ever be.

 

For my first full tankful of gas my MID said 25 MPG @ an avg of 42 MPH for 342 miles, which for me is mostly around town and short hops on the hightway (normally <5 miles at a time). It does not include any time actually stopped in traffic. I was happy with that.

When I actually filled up it took just under 13 gallons to fill (slighly less but I'm sure I could have squeezed a bit more in there to get it to 13). So over 342 miles that's actually 26.3 MPH and I have about 600 miles on the car so I would expect that to improve somewhat over time.

 

Federal speed limit? Uh, no offense, but where have you been for the past few years? The federal speed limit law was repealed in 1995!

 

Just because VA has a speed limit of 65 doesnt mean the rest of the US is the same.
Where I live in NY all the speed limits are still 55 .... upstate NY is generally 65mph.

 

You're missing the point. The point is that there is no federal speed limit--it was repealed effective December 8, 1995, and the states have the authority to set their own speed limits. Outside the northeastern United States, most of the Interstate system is posted at 70 mph or 75 mph, which would have been prohibited under the old federal speed limit. I am THANKFUL that most of the US is not still stuck on the piddling 65 mph that we have in Virginia. It so happens that much of the northeast has stayed with the old speed limits, with a few revisions, but that doesn't mean that the federal speed limit is still in force.

The real benefit of the repeal of the old federal speed limit is that non-Interstates can be posted at speeds higher than 55 mph--for example, expressways that are essentially Interstate look-alikes but that are not badged as Interstates, such as US-50 in Maryland, which is posted at 65 mph but prior to the repeal had to be posted at 55 under federal law.

 

You mean to say that you can't reset whatever display it is that shows MPG, and get an "instant" reading of MPG from that point forward? Don't have a TL; am thinking of getting one.

 

Yes, the computski NEEDS to be reset. For an accurate reading on the highway. I found this out myself. Was wondering why I was seeing like 24MPG on the highway. Then it woke up (my brain that is)... Its an average. So start fresh. Then you'll know. I used it to check my mod's. Like this one........

https://acurazine.com/forums/console-computer-gaming-13/who-lives-farthest-west-besides-me-135905/